The update, released on Thursday, not only fixes the bug that prevented some Mail messages from appearing, but also fixes the pesky bug that strangled Apple Filing Protocol (AFP) file transfers over 802.11ac – Ars Technicareports that after installing the update, the 2013 MacBook Air now enjoys speeds of such transfers more than double what they were before.

The update also fixes a few more niggling issues such as screen savers sometimes not kicking in when they should, and adds improvements to the reliability of Xsan and the transfer of large files over Ethernet, better performance when authenticating to an Open Directory server, and a few other fixes.

You can install the update using Apple's Software Update capability, which launches the OS X App Store app, or if you're running OS X 10.8.4 you can download the update, which varies in size depending upon your Mac, here. The full Combo update, which is 871.5MB and contains all updates since 10.8 appeared, is available here.

Apple also says that you can obtain information about the security updates in 10.8.5 here, but as is apparently a tradition in Cupertino, that information has yet to be posted – check in later today or tomorrow. Or the next day. ®